Improvement in slates



Patented March 6,1877.

`SLATE.

www3

Lawn... MERQ .XN

m Q 888ML ET .TT

G. S. VELEZ.

INVENTUB TTUBMEYS.

N liflZfIIIfl N. PETER;FHOTOLITHOGRAPHEE, WASHNGTON. D C.

UNITED STATES PATENT GEErcE5 GEORGE S. VELEZ, OF NEW YORK, N. Y.

IMPROVEMENT IN SLATES.

Specification forming part of Letters Patent No. 188,083, dated March 6,1877; application led January 29, 1877.

To all whom it may concern:

Be it known that I, GEORGE S. VELEZ, ot' the city, county, and State ofNew York, have invented a new and Improved Multiplication-Slate, ofwhich the following is a specification:

In the accompanying drawing, Figure l represents a top view, and Fig. 2a vertical transverse section on line m x, Fig. l, of my improvedmultiplication-slate.

Similar letters of reference indicate corresponding parts.

The object of this invention is to provide an improved device forfacilitating and expediting the multiplication of larger and smallernumbers by the assistance of mechanical means; and the inventionconsists of a slate with a sliding slate-rule, guided in a slot orrecess of the slate, and worked in connection with the graduated orsubdivided edges ofthe adjoining slate-sections.

In the drawing, A represents a slate, with a longitudinal recess, a, inwhich the sliding rule B is guided, by means of suitable rails b orotherwise.

The sliding rule B is worked by a springbutton, C, in connection with apinion-andrack mechanism, D, or by equivalent mechanism, so that eachdepression of the button O feeds the slide-rule forward the length ofone tooth.

By releasing the check-pawl D', or other check device, the rule B can bemoved or sprung back into its original position, so as to close or tillthe opening or slot ct of the slate.

rEhe sliding rule B is provided with a lling of slate or other material,on which may be written with a slate or other pencil, the slate-fillingbeing divided by cross-lines into subdivisions or sections of such sizethat a gure may be readily and conveniently written into eachsubdivision.

The adjoining sections of the slate A are marked or graduated in thesame manner, so that the dividing-lines of the sliding slate-ruleregister with those of the slate-section.

The guide-rail and rack may be similarly marked, so as to facilitate theregistering of the different dividing-lines, and bring thereby thefigures placed into the subdivisions of the sliding rule and adjoiningslate-sections into corresponding columns.

The multiplication-slate is used as follows, the different operationsbeing accomplished by mental process, without being specially writtendown: The figures of the multiplicand are placedinto the divisions oftheupper section of the slate, and those ot' the multiplier in thedivisions or columns of the slate-rule, but in reversed order, the unitsof the multiplier being placed below the unit figure of themultiplicand, and the tens, hundreds, &c., to the right of the unitligure. Ilie units are then multiplied, and the unit ofthe resultingnumber placed into the column of the lower adjoining slate-section. Thebutton is now depressed, and the slate-rule moved forward so as to bringthe units and tens of the multiplier below the tens and units ofthemultiplicand, after which the units and tens are multiplied and added tothe ligure obtained before by the multiplication of the units. The unitgure of the number so obtained is the ten figure, and is placed in thesecond column adjoining the unit ligure of the result. The slate-rule isthen moved again, and the same operation continued until all the guresof the multiplier have passed below the figures of the multiplicaud, asshown clearly in Fig. 1 by the detailed multiplications accomplishedmentally at each position ot' the slate-rule, and which exemplifyinstantly the method of using the slate.

The mental process necessary is easily learned and quickly accomplished,so that the result may be written off directly into the columns of thelower slate-section, facilitating especially the multiplication oflarger numbers, so as to be useful for schools, business-houses, stores,Src., as a considerable saving of time is obtained, and the number ofmistakes incidental to the present method considerably decreased.

Having thus described my invention, I

I claim as new and desire to secure by Letters Patent- 1. Amultiplication .-slate composed of a. ing slate-rule, and suitablemechanism for slotted slate, with graduated or subdivided moving the'samel forwardand back, substanadjoining sections, and of anintermittently- 1 tially as set forth. sliding and subdividedslate-rule, substantially as and for the purpose set forth.

2. The combination of a slotted or recessed slate, having suitableguide-rails, with a slid- GEO. S. VELEZ. Witnesses:

C. SEDGWIGK,

ALEX. F. ROBERTS.

